Scaffold hoist



Sept. 2 1924. 1,506,865

l E. w.v ROBINSON SCAFFOLD HOIST Filed Aug. 16 1923 Patented Sept. 2, 1924.

UNITED STATES EARL W. ROBINSON, `OF MINNEAPOLIS, MINNESOTA.

soArFoLn HoIsT.

Application filed August 16, 1923. Serial No. 657,767.

To all 'whom t may concern Be it known that I, EARL XV. ROBINSON,

a citizen of the United States, residing at Minneapolis, Vin the county of Hennepin and State of Minnesota,l haveinvented certain new and useful Improvements in Scatfold Hoists, of which the following is a speciA cation.

. This invention relates to scaffold lioists ifi and the main object is toprovide a practical,

eflicient and easily operated means for raising and lowering scaffold platforms such as are commonly used by painters, masons, carpenters and other builders who work on i3' the sides of buildings, boats, etc. Further and more specific objects will be disciosed'in the course of the following specification, the invention being illustrated in the accompanying drawing, wherein:

ifi Fig. 1 is a perspective view ofone end ofy a hanging platform showing the application of myrinvention.

Fig. 2 is an elevation of the hoisting device shown in Fig. 1, kon an enlarged scale if; Vand with portions `broken away.

Fig. 3 is a vertical section on the line 3 3 in Fig. 2. Y Fig. 4 is' an enlarged sectional detail on the line 4 4 in Fig. 2.

Referring to the drawing more specifically and by reference characters 5 designates a main housing, having a hook 6 from which one end of a platform 7 is suspended by a 'cable 8. Only one hoisting device is shown,

a but it will, of course, be understood that another will be required at the other end of the platform or scaffold to be raised or lowered.

rfhe device is suspended from the roof or if.) a window, or other suitable support, in the usual manner, by a long cable which eX- tends down into the housing 5 and is wound upon a drum 10. The drum on a shaft 11,'which is journaled in the housing 5, and carries a worm gear 12 meshing with a worm 13 on a shaft 14. The worm shaft is provided with a bearing inember 15, journaled in the housing. The pin 16 is detachably secured in the housing, and

normally retains the member V15 in rotatable but non-slidable position in thehousing by engaging in a peripheral groove 17 therein. A hand crank 18 is secured on the end of the shaft 14.

is fixed As the weight of the scaffold is always on the cable 9 it will be understood that the worm gear 12 will always act against theY worm13 in the direction indicated by Vthe arrow A, and that therefore there can be i' Vno tendency for the worin or its shaft 14 to work out of the housing in the direction of the handle 18. If, however, it is desired to unwind a long stretch of the cable 9, as when the scaffold is on the ground and the cableis to be pulled up for engagement with its hanging support, then the pin 16 is extractedand the handle 18 is turned to the left, in a counter-clockwisedirection, thus screwing the worm 13 ofin of the gear 12. rIhis will leave thedr'um 10 free to rotate so that the cable can be freely and quickly pulled out of the housing to the desired extent, at which time the Vworm is again engaged and the pin 16 is re-inserted.l 'Y

It will thus be readily understood that, under normal circumstances, the drum will be 'locked in any position to which it is turned, by the worm 13; and can be turnedA only by the crank 18, to adjust the lengthV of the cable 9 and the height of the scaffold platform 7. l

It is further understood that suitable modifications may be made in the general designand structural details of the invention, asA herein disclosed, provided, however, that such modifications come within the spirit and scope of the appended claim. Having now, therefore, fully shown and described my inventiom what I claim to be new anddesire to protect by United States Letters Patent is:V

In a scaffold hoist, the combination with a body member, of a drum journaled therein, a cable lhaving its lower end wound upon the drum to carryV the weight of the hoist and scaold, a worm gear for turning the drum, a-worm shaft having a worm at one end meshing with said gear, and a crank at the other end to turn the shaft, means for slidably journalingthe shaftso that said worin may be moved longitudinally into or out of engagement with the worm gear, a bearing member on the shaft having a peri heral roove' anda in removabl secured f P i V 105 

